Lock



July 20,1926. 1,593,513

- E. B. STONE LOCK I Filed, May 23, 1923 ,q Tam/Ex.

Patented July 20, 1926.

UNITED STATES r raNrjo-Fncs.

ELHER B. STONE, or new Bnrrnm, connncrrcu'r, .ASSIGNOR T O THE-AMERICAN HARDWARE CORPORATION, on NEW BRITAIN, connnc'rrcu'r, A conronn'rron or CONNECQIGUT.

1 LOCK.

Application filed. my 23,

My invention relates to that class of looks more commonly known as pin tumbler locks, and an object of my invention, among others, is the construction of a lock of this class, whereby the chance of operating it without a key, or without a-keyespecially designed for it, shall be reduced to a minimum; and a further object of the invention, is to provide a lock of this class that shall not require extreme care and precision in its construction.

One form of a lock embodying my invention, and in the construction anduse of which the objects herein set out, as well as others, may be attained, is illustrated in the accompanying drawings, in which.

Figure 1 is a view in cross section through the cylinder and plug or barrel of my improved lock on a plane passing through one of the tumbler sockets, the tumbler being shown in full.

Figure 2 isa side view of the cylinder partially broken away in central lengthwise section.

Figure 3 is a side view of the key for operating the lock.

Figure 4 is ,a'view, scale enlarged, in cross section through a fragment, of the lock cylinder and plug illustrating its operation.

Figure 5 is a similarviewfurther illustrating the operation of the lock member.

Figure 6 is a view-on a plane passing centrally lengthwise through the plug, a fragment of which together with thecylinder isshown, and illustrating the position 0% the tumbler to permit rotation of the Heretotore, in the construction of locks of this class, great care and precision have been required, as well as much care and skill to assemble the parts, to avoid looseness, and especially after some'wear, to an extent to cause the parts to stick in operation, and it vised a lock embodying my invention illustrated and described herein. Such lock com rises a plug'or barrel 7 fitted within a cy inder 8, said plugvhaving a slot 9 for the reception of a key 10, an actuator 11 being secured to the end 01 the plug projecting from the cylinder forthe purpose oil actuating a lock or other member in a manner that will be readily understood, all

' made so that they are sgmewhat loose in is to avoid these objections that l have ole:

1928, Serial No. 640,870.

of the parts thus' far described being of old and well-known-construction; 4 Tumbler sockets 12 are formed in the plug, and a tumbler case 13 projects from the cylinder i and is provided with tumbler sockets 14, a setof tumblers-being located in the sockets in the plug, and another set of tumblers being located in the sockets in said case,- in a manner common to prior devices of this kind.

When the tumblers are in their normal po sitions, as shown in Figure 2 the outer set" of tumblers project into the sockets in the plug or barrel and thereby prevent the plug from bein turned. When the key 10 is inserted, t e notches 15 therein in which 7 the ends thereof squarewith the axis, if

their sockets will-permit a slight rotatable play of the plug so that the sockets'common to each air of tumblers in the plug) and in the tumbler case will not register, ut will present a shoulder at the entrance of the socketin the plug on one side and at the entrance of the socket in the tumbler case on the opposite side in the path of movement of the tumblers, and as shown in Fig. 4 ofthe drawings, that will either cause the tumblers to stick or that will prevent their movement. If the plug be constructed loose enough to permit a little endwise-play the same conditions will arise as just, above de scribed, except that the shoulders in the tumbler sockets will be located at right angles to thepositions above described.

lln either event the movement of the-key into its slot is either rendered dificultor is prevented, and therefore it has been es-- sential, rior to my invention, that the parts of the lock shall be made with precision and accuracy. I

In order to avoid these requirements for accuracy and precision in construction oi" parts and in the assembly of such parts, ll

mitted looseness between the parts of the lock, will come in contact with shoulders 18-19 hereinabove referred to and will permit the tumblers to slip past the corners and into the sockets 14 in the case 13 as the higher portions of the key raise the tumblers above the positions occupied by them when the key is fully inserted and the tumblers rest on the bottoms of the notches in the key. The key is thus permitted easy and ready entry into the key slot, even though a certain permissive looseness is present in the fit between the lock members. In order that the tumblers thus formed and having a loose fit, as above described, shall not permit rotation of the plug by the operation of a key not intended for the lock, a guard 20, in the form of a projection from the end of each of the tumblers of the lower set, is provided, the outer ends of these guards being rounded, preferably on a radius slightly less than the radius of the key lug, and the undersides of these guar s are undercut as shown especially in Figures 4 and 5 of the drau ings, providing acute angular corners 21. Guards 22 are also provided on the upper set of tumblers, of the same construction as, those just described as to the lower tumblers.

if an attempt be made to operate the look by a key having shallower notches than those on the key intended for the lock, the guards 20 on the lower set of tumblers will project into the tumbler sockets 14 in the case 13, and when the plug is rotated to a slight extent by this ke said guards will be carried against the wa s'of the sockets 14 and this will prevent further rotation of the lug. Further than this the tumblers will e tipped, as shown in Fig. 4, so that the corners of the shoulders 18 will project into the recesses formed b the beveled under surfaces of the guar s and thus tend todraw the guards furtherinto such sockets, and this increases the efiiciency of the guards in respect.

If a key having notches deeper than those of the key intended for operation of the lock be emlployed, the tumblers of the upper set wi rest below their proper levels and the guards 22 will be located in the sockets 12 in the plug, and the same efiect as just described with respect to the lower tumblers will be obtained by the action of the upper set of tumblers.

When an attempt is made to pick a look by means of a wire'inserted in the key slot ofa lock of the prior art to raise the tumblers to their roper sitions, force is ap-v plied to the p 11g, as y an instrument inserted in the key slot, and it is rotated slightly until stopped b one of the tumblers of the u per set. L as of the tumblers only will do t is, as it is practically impossible to make the look so that more than one of the tumblers will act in this way. A Wire is inserted and by feeling the binding tumbler is located. Pressure on the plug is now slightly released just enough to permit the bindin tumbler to be raised, and when it reaches its proper position, a slight further rotation of the plug will take place until stopped by the next tumbler, the lower end of the tumbler first raised now resting on the edge of the plug projecting slightly underneath the sockets 14. The wire is removed from en agement with said tumbler. that is now hel as described, and the same 0 eration is repeated with the second tnnr b er found to bind, and so on until all the tumblers have been properly located when the plug may be turned.

If this 0 eration be attempted in my improved locli, the binding tumbler of the u per set may be located and raised, as a ove described, but this binding action will cease before the tumbler is raised to its proper position, owing to the presence of the ard that is smaller in diameter than the ody of the tumbler. The element of feeling out is therefore removed before the tumblers are raised to their positions to permit rotation of the plug, at the time of removal of this feeling out element the guard on a tumbler in one plug or cylinder member projecting into a socket in t e other plug or cylinder member and tlvus preventing further rotation of the In order to further increase the resistance to movement of the plug and thereby increase the difiiculty of surreptitious operation of the parts, the walls of the soc ets 14 and 12 are roughened, as at 23, and this will so increase the friction that en agement of the guards with the roughene surface will increase to a material extent the movement of the tumblers, when such movement is attempted b means other than the key design for the ock in which the tum-v blers are located.

In accordance with the provisions of the patent statutes 1 have described the principles of operation of my invention, to ther with the device which I now consi er to represent the best embodiment thereof; but I desire to have it understood that the device shown is onl illustrative, and that the invention may e carried out by other means and applied to uses other than those above set out.

I claim 1. A pin tumbler comprising a body having arelieved corner at that end to be 10- catedat the plane of separation between the plug and cylinder to promote ease of movement of said tumbler into its socket, and a guard extending from the end of said body and smaller in diameter than said body.

2. A pin tumbler comprising a body havinga relieved -corn er at that end to be lo cated at the plane of separation between the plug and cylinder, and a guard smaller in I diameter than saidbody and extending from the end thereof and having a rounded end.

3.' A pin tumbler comprising a body having a relieved corner at that endto be 10- undercut side wall. I

5. A lock comprisin a cylinder, a plug located in said cylin er, pin tumblers located in said plug, a pin tumbler located in a socket in said cylinder'and comprising a body having a relieved corner at that end at the mouth of said socket, and a ard rojecting from saidbody and smal er in 'ameter than said body..- 7 6. A lock comprising a, cylinder, a plug located in said cylinder, a pin tumbler loand having an 'uncated in said plug,-a pin tumbler located in said cylinder, said tumblers fitting loosely within the plug and cylinder to allow a slight permissive tipping movement thereof,

each of said pin tumblers having-a bodywith a relieved corner at that. end appurtenant to the other tumblerto promote ease of -movement of said tumbler into its socket,

and a guard-projecting from that end ofeach tumbler having a relieved corner.

located in said cylinder, a pin tumbler 10- 7. A lock comprising a cylinder, a plug cated in said plug, a pin tumbler located in said cylinder, each of said tumblers having a-body with a relieved corner at that end appurtenant to the other tumbler, and a guards each belng smaller in diameter than said body and having an undercut wall.

8. A lock comprising a pin tumbler element, anda member having a socket element for movement thereinto of saidpin tumbler element, one of said elements having a relieved corner to permit movement of said tumbler when out of line with saidsocket.

; ELMER B. STONE. r

"guard projecting from that end of each 4 .tumbler having a relieved corner, vsaid 

